Planting the Seeds of Drought Resistance

The chemical structure of Abscisic acid, the key to creating drought-resistant plants.

Abscisic acid, protein phosphatases, 14N/15N metabolic labeling and Arabidopsis thaliana are all words that most rational human beings wouldn’t immediately recognize. But get ready, my friend. You’re about to have a crash course in modern genetics and how they could save the world from famine in a warming climate.

Abscisic acid (ABA) is an extensively studied hormone found in plants that controls seed dormancy and germination. If you’ve ever performed that middle school experiment where you grow plants in a plastic bag filled with seeds and a wet paper towel, then you’ve seen the hormone in action. The seeds stay dormant and virtually impervious to the outside world until introduced to a climate suitable for it to sprout to life.

But ABA isn’t important only to the seed stage of a plant’s life. As it matures, the hormone also controls how the plant reacts to stressful situations like not having enough water to survive. As a plant dries up, it shrivels, closes its pores and goes into a state of relative dormancy in order to conserve its resources. However, there is a threshold after which there is no return and dormancy turns to death.

Understanding how ABA controls a seed’s dormancy – which needs only about 10 percent water to remain viable – and how it in turn controls a plant’s reaction to drought – which needs about 90 percent water to survive – could help engineer a plant that can withstand drier climates.

Moving down the vocabulary list, we now come to protein phosphatases. These tongue-tanglers are a particular type of protein called an enzyme, which controls the rates of chemical reactions. All living organisms have thousands them, but only a few are affected by ABA. Finding out which ones was the whole point of a study by Kelli Kline, Gregory Barrett-Wilt, and Michael Sussman of the University of Wisconsin’s Biotechnology Center and Department of Biochemistry recently published in the Proceedings of the National Academy of Science (PNAS).

This brings us to 14N/15N metabolic labeling and Arabidopsis thaliana. The former is a brand new technique using an isotope of nitrogen to identify proteins in living plant cells, which made this entire study possible. The latter is the Latin name of the model laboratory plant used in the study.

Putting it all together, out of the 30,000 phosphatases that exist in a plant’s genome, the researchers were able to identify 50 that are affected by ABA in the plant Arabidopsis thaliana using a new tagging technique that utilizes the isotopes 14N/15N. Of those 50 enzymes, 4 of them affected the plant in a way believed to close off its pores in order to conserve water.

With this new information in hand, scientists hope to continue their studies by finding new substances that can bind to these proteins in the same manner and cause the same reaction. If successful, these compounds could be applied to crops in order to induce them to close their pores and prepare for some hard times before actually being hit by them.

And, in fact, it seems that they’re already hot on the trail.

For more information from Wisconsin’s own press release – which is very well written I might add – read this.

And here is the same story from U.S. News.

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About bigkingken

A science writer dedicated to proving that the Big Ten - or the Committee on Institutional Cooperation, if you will - is more than athletics.
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